Wednesday, September 30, 2009

How to Convert ArcINFO Interchange Files (.e00) to Shapefiles (.shp)

Back in the days of ArcINFO, interchange files, also known as export files (.e00) were used to package directory based data types (coverages and grids) into a single file so they could be transferred between different machines. Though ArcINFO interchange files are used less frequently today, it is not uncommon to come across this file type. So the question is, how do you convert an export file (.e00) to shapefile (.shp) format? There are actually a couple ways. The easiest way is to use ArcGIS Desktop (ArcView, ArcEditor, or ArcInfo license level). I explain how to do this step-by-step below. However, if you do not have ArcGIS Desktop, you can install a couple of free tools to achieve the same results. See the Converting E00 Vector Data To Shapefiles – A Free and Fairly Painless Approach entry on the Free Geography Tools blog for information on and links to the free tools available for the conversion.

Conversion Using ArcGIS Desktop
Stage 1: Convert ArcINFO interchange file to ArcINFO coverage
1. In ArcCatalog, click the View menu, then click Toolbars, and select ArcView 8x Tools to open the toolbar.
2. Select the Conversion Tools drop-down menu and click on Import from Interchange File…
3. Click the Input file browse button and navigate to the .e00 file to be imported. Once the .e00 file is selected click Open.
4. Click the Output dataset browse button and navigate to the directory where the output coverage will be stored. Provide a name for the coverage and click Save.
5. Click OK.

Stage 2: Convert ArcINFO coverage to Shapefile
6. In ArcToolbox, navigate to the Feature Class to Shapefile tool located in Conversion Tools  To Shapefile.
7. Click the Input Features browse button and navigate to the ArcINFO coverage that was created in Stage 1. Select the coverage and click Add.
8. Click the Output Folder browse button and select the folder where the shapefile will be stored. Click Add.
9. Click OK.

*Important Notes*
• The input .e00 cannot have a space in its name or be stored in a directory that has a space anywhere in the directory’s path.
• The output coverage cannot have a space in its name or be stored in a directory that has a space anywhere in the directory’s path.
• The output coverage cannot be more than 13 characters long, and cannot contain special characters (underscores are okay).

Monday, September 21, 2009

Hawth’s Tools – Free Tools for Spatial Analysis

Hawth’s Analysis Tools provides a suite of solutions for tasks common in spatial analysis. Specifically developed for ecological studies, these tools can be used in any application for analyzing spatial data. They extend (and in some cases simplify) core ArcGIS functionality that is not available out-of-the-box. The extension consists of more than fifty tools that cover a broad range of analysis types including analyzing, sampling, and editing vector as well as raster data, and tools for common operations in tables and CSV files. All tools and descriptions can be found here:

Tool Descriptions

A few of the tools that I have found useful in my work include:
• Create Random Selection tool for selecting specified number or percentage of random features (points, lines, or polygons)
• Generate Random Points tool for generating a defined number of points over a specified area
• Create Vector Grid for generating a grid over a specified area and of a defined grid cell size
• Thematic Raster Summary for summarizing the frequency of cells of categories in a thematic raster layer by polygon
• Sum Values for calculating the total value of all/selected rows in a numeric field
• List Unique Values for listing all unique values in a selected field
• Delete Multiple fields for removing multiple fields from a table all at once
• Intersect Lines for generating point features at line intersections

The tools run on ArcGIS 9.x at the ArcView, ArcEditor, and ArcInfo license levels. *These tools do not support on-the-fly projection changes, so it is important that tools that use more than one input layer have the same projection.

Thursday, September 10, 2009

Online Batch Geocoding – Address Locators and Street Networks A Thing Of The Past

Here’s a handy website that will leave you wondering why you ever dealt with standardizing addresses, building address locators, or trying to find a decent street network for geocoding:

The website uses the Yahoo! Geocoding API to locate street addresses and convert them to latitude and longitude coordinates in decimal degrees using the WGS84 coordinate system. Street level geocoding is available for the United States, Canada, and many European countries (see the Data Coverage section on the website for a complete list). The geocoder runs relatively fast and generates accurate results.

How to use:
Ensure that your address data is broken into four fields:
1. Address (house number, street name, and street type)
2. City
3. State/Province or Country (Europe)
4. Zip/Postal Code

If your data is in an Excel spreadsheet, select all of the cells, click copy, and then paste the contents in the space provided on the website (under step #2). Follow the easy instructions and click Run Geocoder. Once it’s done running, two columns are added to the table for latitude and longitude (bg_lat and bg_long). The results are displayed in a text box under Step #6. Follow the instructions for getting this data back into Excel.

Once you have your data back into Excel, you can easily create point features for your addresses. Ensure the new spreadsheet containing the fields for latitude and longitude is saved. In ArcMap 9.x (with ArcView, ArcEditor, or ArcInfo licenses), select Add XY Data… under the Tools menu.

Locate the Excel spreadsheet and set the X and Y values to the appropriate fields in the table. Select an appropriate coordinate system and click OK.

An event layer containing the point features of your addresses are added to the Table of Contents. *To store this layer as a shapefile or feature class, you must export the features in the event layer.* Do this by right clicking the layer in the Table of contents and selecting Data  Export Data…

Navigate to the appropriate directory for storing the data and click OK.